The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Torque-based control can be implemented for internal combustion engines to achieve a desired drive characteristic. An engine torque-based control system interprets an accelerator pedal position of the vehicle as an engine torque request. The engine is controlled to deliver the requested engine torque to provide the desired drive characteristic. Various torque models exist for predicting engine torque. As can be appreciated, the models are not accurate for all desired drive characteristics.
Errors in the torque models ran affect overall drivability of the vehicle. In particular, errors can affect clunk control. This is particularly true around zero torque when dunk management is active. Conventional systems account for errors in the torque model by applying conservative lash zone boundaries (torque limits bounding zero torque where rate limiting is applied) which are padded to include torque error tolerances. The consequence of this approach is degraded performance. More time is spent getting through the rate limited zone for each torque request that crosses zero thereby, sacrificing the response time of the engine. Better torque accuracy, especially around zero torque, would improve the response time by allowing the size of the lash zone to be reduced.